JP7087914B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

Conventionally, in an image forming apparatus such as an electrophotographic printer, a copying machine, a facsimile, or a compound machine, for example, in a color printer, image forming units of each color are arranged side by side, and a photoconductor drum is attached to each image forming unit. A charging roller, a developer, etc. are arranged. Then, in each image forming unit, the surface of the photoconductor drum uniformly charged by the charging roller is exposed by the LED head to form an electrostatic latent image, and the electrostatic latent image is developed by the developer. A toner image is formed, and a toner image of each color is transferred onto paper by a transfer roller and fixed in a fuser to form a color image (see, for example, Patent Document 1).

Further, in a printer in which the toner image of each color is not directly transferred to the paper but is once transferred to the intermediate transfer belt, the toner image on each photoconductor drum is superimposed on the intermediate transfer belt in the primary transfer unit. The color toner image is transferred to form a color toner image, and the color toner image on the intermediate transfer belt is transferred to the paper in the secondary transfer unit.

In this type of printer, of the toner supplied from the toner cartridge of each image forming unit into the main body of the image forming unit, the toner image is not transferred to the intermediate transfer unit as a toner image in the primary transfer part, but is placed on the photoconductor drum. The residual toner is removed from the photoconductor drum and sent as waste toner to the waste toner storage chamber formed in each toner cartridge. On the other hand, the toner remaining on the intermediate transfer belt without being transferred to the paper as a color toner image in the secondary transfer portion was removed from the intermediate transfer belt and disposed adjacent to the intermediate transfer belt as waste toner. It is sent to the waste toner tank.

In this case, the amount of waste toner sent to the waste toner tank is calculated based on the primary transfer efficiency in the primary transfer unit and the secondary transfer efficiency in the secondary transfer unit, and is based on the calculated amount of waste toner. The amount of waste toner that can be accommodated in the waste toner tank, that is, the remaining volume is calculated.

Then, when the remaining volume of the waste toner tank becomes equal to or less than the threshold value, the printer operator is notified that the remaining volume has become small and is urged to replace the waste toner tank.

Japanese Unexamined Patent Publication No. 2008-23369

However, in a conventional printer, the remaining volume of the waste toner tank cannot be calculated accurately.

For example, in a printer capable of printing using a special color toner such as a white toner or a brilliant toner, an image forming unit of the special color toner is intermediately transferred according to the purpose of use of the special color toner. Since it is necessary to arrange the image forming unit on the most upstream side or the most downstream side in the traveling direction of the belt, each image forming unit is detachably arranged with respect to the printer main body, that is, the device main body, and each is arranged. The position of the image forming unit can be freely set.

Further, in a printer in which each image forming unit is detachably arranged with respect to the main body of the apparatus, an image is used for the purpose of suppressing the consumption of each toner and suppressing the deterioration of each member of the image forming unit. An elevating mechanism for moving the forming unit in the vertical direction and placing it in the up state or down state is provided, and the image forming unit that is not used for printing is placed in the up state, and the photoconductor drum is provided. Is designed to be separated from the intermediate transfer belt.

Therefore, in the printer, when the toner image is transferred to the intermediate transfer belt in the primary transfer unit of the predetermined image forming unit, the toner image on the intermediate transfer belt is subsequently downstream from the predetermined image forming unit. Since the number of times of passing through the primary transfer unit of the image forming unit depends on the position of the predetermined image forming unit and whether or not the image forming unit on the downstream side is placed in the up state, the toner image on the intermediate transfer belt is displayed. The charge distribution of the toner changes each time it passes through the primary transfer section of the image forming unit on the downstream side.

Further, since the height of the primary transfer voltage required to transfer the toner image to the intermediate transfer belt differs depending on the color of the toner, how many colors of the toner image are transferred by the primary transfer unit of the image forming unit on the downstream side. Also, the charge distribution of the toner in the toner image transferred to the intermediate transfer belt changes.

Therefore, in the secondary transfer unit, the secondary transfer efficiency when the toner image on the intermediate transfer belt is transferred to the paper changes, so that the amount of waste toner changes and the remaining volume of the waste toner tank is calculated accurately. Can not do it.

In this case, the operator is urged to replace the waste toner tank even though the remaining volume is actually sufficiently large, or the operator is urged to replace the waste toner tank even though the remaining volume is small. I don't have it.

The present invention provides an image forming apparatus that can solve the problems of the conventional printer, accurately calculate the remaining volume of the waste toner tank, and properly prompt the operator to replace the waste toner tank. The purpose is.

Therefore, the image forming apparatus of the present invention includes an image carrier and a developer carrier that develops an electrostatic latent image formed on the image carrier to form a developer image, and is provided with respect to the main body of the apparatus. A plurality of image forming units movably arranged and arranged so as to face the image carrier of each image forming unit, and one or more driving elements are driven according to an image signal to drive the surface of the image carrier. An exposure device that forms the electrostatic latent image by exposing the image, a first transfer member that transfers the developer image formed on each image carrier to the intermediate transfer member and performs primary transfer, and an intermediate transfer member. The second transfer member that transfers the above developer image to a medium and performs secondary transfer, and the developer image that remains on the intermediate transfer member after the secondary transfer is removed, and the waste developer storage unit A cleaning device housed in, a pattern detection unit that detects a density detection pattern formed on an intermediate transfer member, a position of each image forming unit, a state of detachment of each image forming unit with respect to the intermediate transfer member, and a state of contact with the intermediate transfer member. A density correction processing unit that corrects the density of an image formed on a medium based on the density of the density detection pattern calculated based on the output voltage of the sensor output of the pattern detection unit, the output voltage, and the density detection. Based on the density of the pattern, the amount of waste developing agent generated by printing is calculated, and based on the amount of the waste developing agent, the storage state of the waste developing agent in the waste developing agent storage unit is calculated, and the operator is notified. It has a waste developer amount calculation processing unit.

According to the present invention, the image forming apparatus includes an image carrier and a developer carrier that develops an electrostatic latent image formed on the image carrier to form a developer image, and the apparatus main body thereof is provided with a developer carrier. A plurality of image forming units movably arranged and arranged so as to face the image carrier of each image forming unit, and one or more driving elements are driven according to an image signal to drive the surface of the image carrier. An exposure device that forms the electrostatic latent image by exposing the image, a first transfer member that transfers the developer image formed on each image carrier to the intermediate transfer member and performs primary transfer, and an intermediate transfer member. The second transfer member that transfers the above developer image to a medium and performs secondary transfer, and the developer image that remains on the intermediate transfer member after the secondary transfer is removed, and the waste developer storage unit A cleaning device housed in, a pattern detection unit that detects a density detection pattern formed on an intermediate transfer member, a position of each image forming unit, a state of detachment of each image forming unit with respect to the intermediate transfer member, and a state of contact with the intermediate transfer member. A density correction processing unit that corrects the density of an image formed on a medium based on the density of the density detection pattern calculated based on the output voltage of the sensor output of the pattern detection unit, the output voltage, and the density detection. Based on the density of the pattern, the amount of waste developing agent generated by printing is calculated, and based on the amount of the waste developing agent, the storage state of the waste developing agent in the waste developing agent storage unit is calculated, and the operator is notified. It has a waste developer amount calculation processing unit.

In this case, the medium is based on the position of each image forming unit, the detached state of each image forming unit with respect to the intermediate transfer member , and the density detection pattern density calculated based on the output voltage of the sensor output of the pattern detection unit. Since the density of the image formed in the image is corrected and the amount of the waste developer generated by printing is calculated based on the output voltage and the density of the density detection pattern, the secondary transfer is performed. Even if the transfer efficiency changes, the amount of the waste developer can be calculated accurately.

Therefore, the remaining volume of the waste developer accommodating portion is accurately calculated, and the operator is properly urged to replace the waste developer accommodating portion.

It is a control block diagram of the printer in embodiment of this invention. It is a conceptual diagram of the printer in embodiment of this invention. It is the first figure for demonstrating operation of a density sensor in embodiment of this invention. It is a 2nd figure for demonstrating operation of a density sensor in embodiment of this invention. It is a 3rd figure for demonstrating operation of a density sensor in embodiment of this invention. It is a flowchart which shows the operation of the mechanism control part in embodiment of this invention. It is a figure which shows the example of the 1st image formation unit combination table in embodiment of this invention. It is a figure which shows the example of the development voltage adjustment value table in embodiment of this invention. It is a figure which shows the example of the density | concentration detection pattern in embodiment of this invention. It is a figure which shows the example of the coefficient table for concentration calculation in embodiment of this invention. It is a figure which shows the example of the target print density table in embodiment of this invention. It is a figure which shows the example of the drive time adjustment value table in embodiment of this invention. It is a figure which shows the example of the coefficient table for secondary transfer efficiency calculation in embodiment of this invention. It is a figure for demonstrating the example of the position of each image formation unit in embodiment of this invention. It is a figure which shows the example of the toner color of the toner image transferred in the primary transfer part in embodiment of this invention. It is a relationship diagram of the output voltage and the density | concentration of the density detection pattern when the number of image formation units downstream from the image formation unit which attempts to calculate the density | concentration of the density detection pattern in embodiment of this invention is different. The relationship diagram between the output voltage and the density of the density detection pattern when the toner color of the toner image in the image forming unit downstream from the image forming unit for calculating the density of the density detection pattern in the embodiment of the present invention is different. Is. It is a figure which shows the other example of the density | concentration detection pattern in embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a color printer as an image forming apparatus will be described.

FIG. 2 is a conceptual diagram of a printer according to an embodiment of the present invention.

In the figure, 10 is a printer, Cs is a housing of the printer 10, and Bd is a main body of the printer 10, that is, a main body of an apparatus. The housing Cs includes a front wall Wf, a back wall Wr, and a top wall Wt, and a stacker 18 as a medium loading portion is formed on the top wall Wt. Further, a predetermined portion of the top wall Wt is formed to be openable and closable as a device cover, and the operator can access the device body Bd by opening the device cover. Further, the display unit 19 is arranged in the vicinity of the front wall Wf and the top wall Wt in the device main body Bd.

A paper feeding mechanism M1 is arranged at the lower part of the apparatus main body Bd, an image forming unit Q is arranged at the upper part of the apparatus main body Bd, and a transfer unit u1 is arranged between the feeding mechanism M1 and the image forming unit Q.

The paper feeding mechanism M1 is rotatably arranged in contact with the paper cassette 11 as a medium accommodating portion for accommodating the paper P as a medium and the paper P at the front end of the paper cassette 11, and the paper is rotated as the paper is rotated. A hopping roller 12 as a feeding member for feeding P to a paper transport path Rt1 as a medium transport path, a pinch roller 14 rotatably arranged in the paper transport path Rt1, and a rotatably arranged pinch roller 14 facing the pinch roller 14. A guide 16 as a first guide member arranged on the downstream side of the pinch roller 14 and the resist roller 15 in the paper transport path Rt1 is provided, and the paper P is described later by the guide 16. Guided to the secondary transfer section. Then, the pinch roller 14 and the resist roller 15 correct the skew of the paper P transported on the paper transport path Rt1.

The image forming unit Q has a plurality of (two or more) colors, and in the present embodiment, five color image forming units (image drum unit, printing mechanism) of yellow, magenta, cyan, black, and white as a spot color. ) 20Y, 20M, 20C, 20Bk, 20W are arranged side by side in the horizontal direction so as to be detachably attached to and detachable from the apparatus main body Bd and movable in the vertical direction (arrows U and D directions). The image forming units 20Y, 20M, 20C, 20Bk, 20W may be arranged at arbitrary positions according to the purpose of use of the toner of each color, or the positions of the image forming units 20Y, 20M, 20C, 20Bk, 20W may be exchanged. Can be done. Further, the image forming units 20Y, 20M, 20C, 20Bk, and 20W are moved in the vertical direction by an elevating mechanism (not shown), moved in the arrow U direction, placed in an up state, and separated from the intermediate transfer belt 35. It is moved in the direction of arrow D, placed in a down state, and brought into contact with the intermediate transfer belt 35.

Further, each photoconductor drum 21 as an image carrier is rotatably arranged in each image forming unit 20Y, 20M, 20C, 20Bk, 20W, and is above the photoconductor drum 21 in the apparatus main body Bd. An LED head 24 as an exposure device (exposure unit) is arranged so as to face the photoconductor drum 21.

An image signal of each color is sent to each of the LED heads 24, and when the image signal is sent, each LED head 24 generates light having a pattern corresponding to the image signal and irradiates the surface of the photoconductor drum 21. As a result, the photoconductor drum 21 is exposed to form an electrostatic latent image as a latent image. Therefore, the LED head 24 has an LED array as a drive element array, and one or more of the LED arrays, in the present embodiment, LEDs as a plurality of drive elements (light emitting elements) in a holder (not shown). It is equipped with a drive IC that drives (lights up) and generates the light, a substrate on which a register group that sends data constituting the image signal to the LED, and the like are mounted, and a lens array, and the light generated by each LED. Is focused by the lens array and irradiated on the surface of the photoconductor drum 21.

In addition to the photoconductor drum 21, the image forming units 20Y, 20M, 20C, 20Bk, and 20W also include a toner cartridge 25 as a developer accommodating portion for accommodating toner as a developer and a photoconductor drum 21. A developer that is rotatably arranged in contact with a charging roller 26 as a charging device that is abutted and rotatably arranged and is rotatably arranged in contact with a photoconductor drum 21 to form a developing unit with the photoconductor drum 21. A developing roller 27 as a carrier, a supply roller 28 as a developer supply member rotatably arranged in contact with the developing roller 27, and a developing blade 29 forming a thin layer of toner on the developing roller 27. It is provided with a static elimination device 30 which is arranged to face the photosensitive drum 21 and irradiates the photosensitive drum 21 with static elimination light to eliminate static electricity on the surface of the photosensitive drum 21, a first cleaning device (not shown), and the like. The toner cartridge 25 contains yellow, magenta, cyan, black, and white toners of each color in the present embodiment. The first cleaning device removes the toner remaining on the photoconductor drum 21 after the toner image as a developer image of each color is transferred to the intermediate transfer belt 35 in the primary transfer unit described later.

The surface of the photoconductor drum 21 is uniformly charged by the charging roller 26 and exposed by the LED head 24 to form the electrostatic latent image on the surface of the photoconductor drum 21. Then, the toner supplied from the toner cartridge 25 to the supply roller 28 is supplied to the developing roller 27 and adhered to the electrostatic latent image on the photoconductor drum 21 by the developing roller 27 to form a toner image. Toner. The toner is triboelectrically charged when it is supplied from the supply roller 28 to the developing roller 27 and when it is thinned by the developing blade 29, and is attached to the photoconductor drum 21 by electrostatic force. Further, the developing blade 29 regulates the amount of toner in order to form a thin layer of toner on the developing roller 27.

The transfer unit u1 is rotatably arranged in the vicinity of the image forming unit 20W and the drive roller 31 as a first roller rotatably arranged in the vicinity of the image forming unit 20Y. As a second roller, the driven roller 32, the drive roller 31, and the driven roller 32 are rotatably arranged below the driven roller 32, and are rotated along with the rotation of the drive roller 31 and the driven roller 32. The backup roller 33 as the third roller and the secondary transfer facing roller, the drive roller 31, the driven roller 32, and the backup roller 33, which are rotated by the above, are stretched and driven with a predetermined tension so as to be runnable. The intermediate transfer belt 35 as a transfer medium, which is run in the direction of arrow C along the image forming units 20Y, 20M, 20C, 20Bk, and 20W with the rotation of the roller 31, the driven roller 32, and the backup roller 33, and the intermediate transfer. The transfer roller 41 as the first transfer member and the intermediate transfer belt 35 are arranged so as to face each other of the photoconductor drums 21 of the image forming units 20Y, 20M, 20C, 20Bk, and 20W via the belt 35. The transfer roller 43 as a second transfer member arranged so as to face the backup roller 33, and the driven roller 32 and the backup roller 33 in the traveling direction of the intermediate transfer belt 35 face the intermediate transfer belt 35. The concentration sensor 44 as a pattern detection unit (concentration detection unit) for detecting the concentration detection pattern, that is, the concentration detection pattern Pt1 (FIG. 4) described later, which is arranged so as to be arranged and formed on the intermediate transfer belt 35. A second cleaning device 45 or the like is provided between the backup roller 33 and the drive roller 31 in the traveling direction of the intermediate transfer belt 35 so as to face the intermediate transfer belt 35. The surface of the intermediate transfer belt 35 facing the density sensor 44 is subjected to a process of imparting gloss.

Further, a cover 49 as a covering member is movably and movably arranged between the concentration sensor 44 and the intermediate transfer belt 35 by an opening / closing mechanism (not shown).

The image forming units 20Y, 20M, 20C, 20Bk, and 20W are arranged side by side from the downstream side to the upstream side in the transport direction of the paper P and from the upstream side to the downstream side in the traveling direction of the intermediate transfer belt 35. To. Therefore, as shown in the figure, the image forming unit 20Y is located on the most upstream side in the traveling direction of the intermediate transfer belt 35, and the image forming unit 20W is positioned on the most downstream side in the traveling direction of the intermediate transfer belt 35.

Each transfer roller 41 performs primary transfer by sequentially superimposing toner images of each color on each photoconductor drum 21 and transferring them to an intermediate transfer belt 35, and forms a color toner image on the intermediate transfer belt 35. A primary transfer portion is formed between each transfer roller 41 and each photoconductor drum 21, and in the primary transfer portion, the intermediate transfer belt 35 is pressed against the photoconductor drum 21 by the transfer roller 41 to form a primary transfer nip. It is formed.

The transfer roller 43 performs secondary transfer by transferring the color toner image formed on the intermediate transfer belt 35 to the paper P, and forms the color toner image on the paper P. A secondary transfer portion is formed between the backup roller 33 and the transfer roller 43, and in the secondary transfer portion, the intermediate transfer belt 35 is pressed against the transfer roller 43 by the backup roller 33 to form a secondary transfer nip. It is formed.

The backup roller 33 is formed by a metal shaft (not shown) and a metal roller (not shown) surrounding the shaft. Further, the transfer roller 43 surrounds a metal shaft (not shown) and the shaft, and has a volume resistivity of about 10 ⁷ [Ω · cm] to 10 ⁹ [Ω · cm], and has conductive foaming. Formed by urethane.

The second cleaning device 45 is made of a flexible rubber material or resin material, and scratches the toner remaining on the intermediate transfer belt 35 after the color toner image is transferred to the paper P in the secondary transfer portion. It includes a cleaning blade 47 as a cleaning member to be removed by removing, and a waste toner tank 48 as a waste developer accommodating portion for accommodating the removed toner, that is, the waste toner as a waste developer.

Then, a fixing device 50 as a fixing device (fixing unit) is arranged on the downstream side of the secondary transfer portion in the paper transport path Rt1. The fuser 50 is provided with a heater ht as a heating body such as a halogen lamp inside, and is rotatable by being brought into contact with a heating roller 51 as a first fixing member and the heating roller 51 which are rotatably arranged. A pressure roller 52 as a second fixing member, which is arranged in the above and is rotated along with the rotation of the heating roller 51, and is a color toner image on the paper P sent from the secondary transfer unit. Is heated and pressed to fix it on the paper P to form a color image. A thermistor 53 as a temperature detector is arranged in the vicinity of the heating roller 51, and the temperature of the heating roller 51 is detected by the thermistor 53.

Further, on the upstream side of the pinch roller 14 and the resist roller 15 in the paper transport path Rt1, the paper feed sensor s1 as the first medium detection unit is arranged adjacent to the pinch roller 14 and the resist roller 15. The paper feed sensor s1 detects the paper P that has reached the pinch roller 14 and the resist roller 15. Then, a transfer unit discharge sensor s2 as a second medium detection unit is arranged between the secondary transfer unit and the fuser 50 in the paper transport path Rt1 so as to be adjacent to the secondary transfer unit. The transfer unit ejection sensor s2 detects the paper P separated from the intermediate transfer belt 35, thereby monitoring the winding of the paper P around the transfer roller 43, the failure to separate the paper P from the intermediate transfer belt 35, and the like. Will be done.

Further, a guide 55 as a second guide member is arranged along the paper transport path Rt1 on the downstream side of the transfer unit discharge sensor s2 in the paper transport path Rt1, and is separated from the intermediate transfer belt 35 by the guide 55. The paper P is supported from below and guided to the fuser 50.

Then, the fixing unit discharge sensor s3 as the third medium detection unit is arranged close to the fixing device 50 on the downstream side of the fixing device 50 in the paper transport path Rt1. The fixing unit ejection sensor s3 detects the paper P ejected from the fixing device 50, and thereby monitors the jam of the paper P in the fixing device 50, the winding of the paper P around the heating roller 51, and the like.

Further, a guide 56 as a third guide member is arranged on the downstream side of the fixing portion discharge sensor s3 in the paper transport path Rt1, and the paper P is guided to the stacker 18 by the guide 56. Along the guide 56, from the upstream side to the downstream side in the paper transport path Rt1, the transport roller pair m1 as the first transport member, the transport roller pair m2 as the second transport member, and the third transport member. The paper P on which the color image is formed, in which the discharge roller pair m3 is arranged and discharged from the fuser 50, is conveyed by the transport rollers pair m1 and m2, and is conveyed from the discharge port h1 by the discharge roller pair m3. It is discharged to the outside and loaded on the stacker 18.

An discharge sensor (not shown) is arranged in the vicinity of the discharge port h1. The discharge sensor detects the rear end of the paper P discharged from the discharge port h1.

Next, the density sensor 44 will be described.

FIG. 3 is a first diagram for explaining the operation of the concentration sensor according to the embodiment of the present invention, and FIG. 4 is a second diagram and FIG. 5 for explaining the operation of the concentration sensor according to the embodiment of the present invention. FIG. 3 is a third diagram for explaining the operation of the concentration sensor according to the embodiment of the present invention.

In the figure, 35 is an intermediate transfer belt and 44 is a concentration sensor.

The density sensor 44 is a reflection type light sensor having one light emitting system and two light receiving systems, and is a concentration detection pattern Pt1 formed on an intermediate transfer belt 35 by a concentration correction processing unit Pr1 (FIG. 1) described later. Detection sites formed in yellow, magenta, cyan and white colors, and detection sites formed in black color are detected. Therefore, the density sensor 44 generates an infrared LED 57 as a light emitting unit that generates light em for density detection and irradiates the intermediate transfer belt 35, and diffusely reflected light of the light em generated by the infrared LED 57. It includes a phototransistor 58 as a first light receiving part that receives re1, and a phototransistor 59 as a second light receiving part that receives the mirror-reflected light re2 of the light em generated by the infrared LED 57.

When detecting the detection site formed by the colors of yellow, magenta, cyan and white in the concentration detection pattern Pt1 formed on the intermediate transfer belt 35, it was generated by the infrared LED 57 as shown in FIG. When the light em is irradiated on the concentration detection pattern Pt1, the phototransistor 58 receives the diffusely reflected light re1 and generates a sensor output of a voltage corresponding to the amount of the diffusely reflected light re1. When there is a lot of toner in the detection area formed of yellow, magenta, cyan and white colors in the density detection pattern Pt1 and the density is high, the amount of diffuse reflected light re1 becomes large, and the voltage of the sensor output of the phototransistor 58, that is, , The output voltage becomes high.

Further, when the detection portion formed by the black color in the density detection pattern Pt1 formed on the intermediate transfer belt 35 is detected, the light em generated by the infrared LED 57 has a density as shown in FIG. When the detection pattern Pt1 is irradiated, the phototransistor 59 receives the mirror-reflected light re2 and generates a sensor output of an output voltage corresponding to the amount of the mirror-reflected light re2. Since the toner in the detection portion formed by the black color in the density detection pattern Pt1 absorbs the light em, the toner in the portion formed by the black color is small, and when the density is low, the amount of light reflected by the mirror surface re2 is large. Therefore, the output voltage of the sensor output of the phototransistor 59 becomes high. On the other hand, when there is a large amount of toner in the portion formed of the black color and the density is high, the amount of specularly reflected light re2 is small, and the output voltage of the sensor output of the phototransistor 59 is low. Therefore, in order to improve the density detection accuracy of the density detection pattern Pt1 by the phototransistor 59, as described above, a process of imparting gloss to the surface of the intermediate transfer belt 35 facing the density sensor 44 is performed, and the intermediate is intermediate. The mirror reflectance of the transfer belt 35 is uniformly and high.

The infrared LED 57 and the phototransistor 59 are arranged so that the incident angle of the light em with respect to the normal line of the radiation surface Sa of the light em in the intermediate transfer belt 35 and the reflection angle of the mirror-reflected light re2 are equal to each other. The LED 57 and the phototransistor 58 are arranged adjacent to each other so that the light em and the diffusely reflected light re1 do not interfere with each other.

As described above, the cover 49 is movably and movably arranged between the concentration sensor 44 and the intermediate transfer belt 35 by the opening / closing mechanism. The cover 49 is retracted so that the density sensor 44 and the intermediate transfer belt 35 face each other while the density correction process described later is being performed, and the toner and paper are being retracted so that the density sensor 44 and the intermediate transfer belt 35 face each other. The density sensor 44 is covered so that the density sensor 44 is not contaminated by powder or the like.

Further, the cover 49 is used as a reference reflector for adjusting the light emission current when the light em is generated in the infrared LED 57. Therefore, the surface of the cover 49 is formed so as to have a preset reference diffuse reflectance.

Next, the control device of the printer 10 will be described.

FIG. 1 is a control block diagram of a printer according to an embodiment of the present invention.

In the figure, 60 is a command / image processing unit as a first control unit and a print information processing unit, 61 is a mechanism control unit as a second control unit, and If 1 is a host interface as a first interface. Unit, If2 is an LED head interface unit as a second interface, 64 is a storage unit for mechanism control, and 65 is a high-voltage control unit connected to a power supply device (not shown) of the printer 10.

The host interface unit If1 consists of a connector and a chip for communication, functions as a physical hierarchical interface with a host computer (not shown) as a higher-level device (external device), and commands and prints sent from the host computer. Receive data.

The command / image processing unit 60 comprises a microprocessor (CPU) (not shown), a RAM (not shown) as a first storage unit for information processing, and special hardware (not shown), and controls the entire printer 10. At the same time, the print data sent from the host computer is interpreted according to the command, expanded into a bitmap, the bitmap data as image data is generated, and recorded in the RAM.

The LED head interface unit If2 is composed of a RAM (not shown) as a second storage unit for information processing and a semi-custom LSI, and the bit map data generated by the command / image processing unit 60 is made to correspond to each LED head 24. To generate an image signal of each color and send it to each LED head 24.

The mechanism control unit 61 includes a microprocessor (CPU) (not shown), a RAM (not shown) as a first storage unit for mechanism control, a ROM (not shown) as a second storage unit for mechanism control, and the like. According to the command of the image processing unit 60, the hopping motor Mt1 as the driving unit for feeding is received from the sensor outputs from the paper feed sensor s1, the transfer unit discharge sensor s2, the fixing unit discharge sensor s3, the concentration sensor 44, the thermista 53, and the like. Driven via a driver to rotate the hopping roller 12, drive the resist motor Mt2 as a drive unit for paper feeding via the driver, rotate the resist roller 15, and use it as a drive unit for running a belt. The belt motor Mt3 is driven via a driver to drive the intermediate transfer belt 35 by rotating the drive roller 31, or the fixing motor Mt4 as a driving unit for fixing is driven via the driver to drive the heating roller 51. The drum motor Mt5 as a drive unit for rotating or image formation is driven via a driver to rotate each photoconductor drum 21, and the transport motor Mt6 as a drive unit for transport is driven via a driver. , The transport roller pair m1 and m2 and the discharge roller pair m3 are rotated, the concentration of the concentration detection pattern Pt1 is detected, and the heater ht is turned on and off.

Further, the mechanism control unit 61 has a concentration correction processing unit Pr1 and a waste toner amount calculation processing unit Pr2 as a waste developer amount calculation processing unit.

The concentration correction processing unit Pr1 forms a concentration detection pattern Pt1 (FIG. 4) on the intermediate transfer belt 35, calculates the concentration of the concentration detection pattern Pt1 by the concentration sensor 44, and uses the calculated concentration of the concentration detection pattern Pt1 as the calculated concentration. Based on this, the development voltage and the driving time of the LED of each LED head 24 are corrected to correct the density of the color image formed on the paper P.

The waste toner amount calculation processing unit Pr2 calculates the amount of waste toner in the second cleaning device 45 (FIG. 2), and calculates the remaining volume of the waste toner tank 48 based on the amount of the waste toner. The remaining volume is displayed on the display unit 19.

Various control parameters, set values, data of the concentration detection pattern Pt1 and the like are recorded in the storage unit 64. Further, in the storage area of the storage unit 64, a first image forming unit combination table Tb1 (FIG. 7), a development voltage adjustment value table Tb2 (FIG. 8), and a coefficient calculation coefficient table Tb3 (FIG. 10), which will be described later, are used. A target print density table Tb4 (FIG. 11), a drive time adjustment value table Tb5 (FIG. 12), a coefficient table for calculating secondary transfer efficiency Tb6 (FIG. 13), and the like are formed.

The high-voltage control unit 65 is composed of a microprocessor or a custom LSI (not shown), and includes a charging voltage generating unit Pw1, a developing voltage generating unit Pw2, a supply voltage generating unit Pw3, a primary transfer voltage generating unit Pw4, and a secondary transfer voltage generating unit Pw5. Be connected.

Then, in response to the instruction from the mechanism control unit 61, the high voltage control unit 65 transfers the charge voltage generated by the charge voltage generation unit Pw1 to the charging roller 26 and the development voltage generated by the development voltage generation unit Pw2 to the development roller 27. The supply voltage generated by the supply voltage generation unit Pw3 was generated in the supply roller 28, the primary transfer voltage generated by the primary transfer voltage generation unit Pw4 was generated in the transfer roller 41, and the secondary transfer voltage was generated by the secondary transfer voltage generation unit Pw5. The next transfer voltage is applied to the backup roller 33.

In the present embodiment, each image forming unit 20Y, 20M, 20C, 20Bk, 20W is moved in the vertical direction (arrow U, D direction) by the elevating mechanism as described above, and is moved in the arrow U direction. It is placed in the up state, separated from the intermediate transfer belt 35, moved in the direction of arrow D, placed in the down state, and brought into contact with the intermediate transfer belt 35. In the present embodiment, printing can be performed with the image forming units 20Y, 20M, 20C, 20Bk, and 20W removed from the device main body Bd. Therefore, for the purpose of explaining the operation of the printer 10, the device main body Bd The state of being removed from the printer is also considered to be up.

When the image forming units 20Y, 20M, 20C, 20Bk, and 20W are placed in the up state, each photoconductor drum 21 is separated from the intermediate transfer belt 35, and at this time, the charging voltage, the developing voltage, the supply voltage, and the primary transfer are transferred. No voltage is applied to the charging roller 26, the developing roller 27, the supply roller 28 and the transfer roller 41.

Next, the operation of the printer 10 will be described.

First, a normal printing operation of the printer 10 will be described.

When the host interface unit If1 receives the command and print data sent from the host computer, the command / image processing unit 60 turns on the heater ht in the mechanism control unit 61 and starts heating the heating roller 51 (warm-up). The print data is interpreted according to the command, expanded into a bitmap, the bitmap data is generated, and the data is recorded in the RAM.

Subsequently, the mechanism control unit 61 drives the fixing motor Mt4 to rotate the heating roller 51, and controls the on / off of the heater ht based on the temperature of the heating roller 51 detected by the thermistor 53 to control the heating roller. The temperature of 51 is set to be the set temperature.

Bitmap data for each color printed on the paper P is recorded in the RAM, and when the printable condition is satisfied when the fixing temperature of the heating roller 51 reaches the set temperature, the command / image processing unit 60 Sends a printing start command to the mechanism control unit 61.

As a result, the mechanism control unit 61 drives the drum motor Mt5 to rotate each photoconductor drum 21, the developing roller 27 and the supply roller 28, and also drives the belt motor Mt3 to rotate the driving roller 31 for intermediate transfer. The belt 35 is run, the fixing motor Mt4 is driven, and the heating roller 51 is rotated.

Further, the mechanism control unit 61 applies the charging voltage generated by the charging voltage generating unit Pw1 to the charging roller 26, applies the developing voltage generated by the developing voltage generating unit Pw2 to the developing roller 27, and supplies the voltage. The supply voltage generated by the generating unit Pw3 is applied to the supply roller 28.

As a result, the surface of the photoconductor drum 21 is uniformly charged with a negative polarity by the charging roller 26. Further, the toner supplied to the supply roller 28 is negatively charged by friction between the developing roller 27 and the developing blade 29, and is supplied to the developing roller 27 by the potential difference between the developing roller 27 and the supply roller 28 for development. In the roller 27, the layer is thinned to a uniform thickness by the developing blade 29.

Further, the command / image processing unit 60 reads out one line of bitmap data from the RAM in which the bitmap data is recorded and sends it to each LED head 24 via the LED head interface unit If2. In the LED head 24, the light generated by driving the LED corresponding to the bitmap data is irradiated on the surface of the photoconductor drum 21, and the static light for one line corresponding to the bitmap data is applied to the photoconductor drum 21. An electro-latent image is formed. Then, the command / image processing unit 60 reads out the bitmap data for one line, repeatedly forms the electrostatic latent image for one line, and forms the electrostatic latent image for one page.

Subsequently, while the electrostatic latent image is formed, the portion of the photoconductor drum 21 on which the electrostatic latent image is formed is between the developing roller 27 and the photoconductor drum 21 as the photoconductor drum 21 rotates. When it reaches the developing unit, an electric field is formed in the direction of the developing roller 27 from the portion of the photoconductor drum 21 where the electrostatic latent image is formed, whereby the toner on the developing roller 27 adheres to the electrostatic latent image. , A toner image is formed.

At this time, in the image forming unit of the image forming units 20Y, 20M, 20C, 20Bk, and 20W, which is placed in the up state, the toner image is not formed on the photoconductor drum 21.

Further, while the toner image is formed on the photoconductor drum 21, the mechanism control unit 61 generates a primary transfer voltage by the primary transfer voltage generation unit Pw4, applies it to the transfer roller 41, and generates a secondary transfer voltage. A secondary transfer voltage is generated by the unit Pw5 and applied to the backup roller 33.

As a result, the toner image on each photoconductor drum 21 is electrostatically sequentially superimposed and transferred on the intermediate transfer belt 35 by the transfer roller 41, and a color toner image for one page is formed.

Then, when the color toner image approaches the secondary transfer unit as the intermediate transfer belt 35 travels, the mechanism control unit 61 drives the hopping motor Mt1, the resist motor Mt2, and the transfer motor Mt6 to rotate the hopping roller 12. Then, the paper P is fed out from the paper cassette 11. When the front end of the paper P reaches between the pinch roller 14 and the resist roller 15, the hopping motor Mt1 is stopped and the hopping roller 12 is idled.

After that, the pinch roller 14 and the resist roller 15 are rotated, the paper P is sent to the secondary transfer unit, and the color toner image on the intermediate transfer belt 35 is transferred to the paper P.

Subsequently, the paper P is guided to the fuser 50 by the guide 55.

When the paper P reaches the fuser 50, the color toner image on the paper P is heated by the heating roller 51 maintained at the set temperature, and is pressurized by the pressure roller 52 to be fixed on the paper P. As a result, a color image is formed on the paper P.

As described above, the paper P on which the image is formed is conveyed along the guide 56 by the transport rollers pair m1 and m2, discharged from the discharge port h1 by the discharge roller pair m3, and discharged to the outside of the apparatus main body Bd by the discharge roller pair m3. Will be loaded into.

When the discharge sensor arranged in the vicinity of the discharge port h1 detects the rear end of the paper P and supplies the sensor output to the mechanism control unit 61, the mechanism control unit 61 allows the paper P to move from the discharge port h1 to the device main body. It is detected that the motors are discharged to the outside of the Bd and loaded on the stacker 18, and the resist motor Mt2, the belt motor Mt3, the fixing motor Mt4, the drum motor Mt5, and the transfer motor Mt6 are stopped. When the toner image is transferred to the intermediate transfer belt 35, in each image forming unit 20Y, 20M, 20C, 20Bk, 20W, the charging voltage is generated by the charging voltage generating unit Pw1 and the developing voltage is generated by the developing voltage generating unit Pw2. The generation, the generation of the supply voltage by the supply voltage generation unit Pw3, and the generation of the primary transfer voltage by the primary transfer voltage generation unit Pw4 are stopped.

By the way, when the toner image is transferred to the intermediate transfer belt 35 in a predetermined image forming unit among the image forming units 20Y, 20M, 20C, 20Bk, and 20W, for example, the primary transfer unit of the image forming unit 20C. After that, the number of times the toner image passes through the primary transfer unit of the image forming unit 20Bk, 20W on the downstream side of the image forming unit 20C is such that the position of the predetermined image forming unit 20C and the image forming unit 20Bk, 20W are up. Since it differs depending on whether or not it is placed, the toner charge distribution of the toner image transferred to the intermediate transfer belt 35 changes each time it passes through the primary transfer unit of the image forming unit 20Bk, 20W on the downstream side.

Further, since the height of the primary transfer voltage required to transfer the toner image to the intermediate transfer belt 35 differs depending on the color of the toner, what color of toner image is displayed in the primary transfer unit of the image forming unit 20Bk and 20W on the downstream side. The toner charge distribution of the toner image transferred to the intermediate transfer belt 35 also changes depending on whether the toner is transferred in layers.

Therefore, the density of the color image formed on the paper P changes, and the image quality deteriorates.

Therefore, in the present embodiment, the density correction processing unit Pr1 of the mechanism control unit 61 determines the positions (arrangements) of the image forming units 20Y, 20M, 20C, 20Bk, 20W, and the image forming units 20Y, 20M, 20C. Based on the up-down state as a detached state indicating whether 20Bk and 20W are placed in the up state and separated from the intermediate transfer belt 35 or placed in the down state and in contact with the intermediate transfer belt 35. The development voltage applied to each developing roller 27 and the driving time of the LED in each LED head 24 are corrected, and the density of the color image formed on the paper P is corrected.

Immediately before printing is started for a predetermined print job, the positions and up / down states of the image forming units 20Y, 20M, 20C, 20Bk, and 20W may be changed. It was determined whether the position and up / down state of the image forming units 20Y, 20M, 20C, 20Bk, 20W were changed, and the position and up / down state of each image forming unit 20Y, 20M, 20C, 20Bk, 20W were changed. In this case, the density correction processing unit Pr1 corrects the development voltage and the LED drive time based on the positions of the changed image forming units 20Y, 20M, 20C, 20Bk, and 20W and the up / down state.

Next, the operation of the mechanism control unit 61 will be described.

6 is a flowchart showing the operation of the mechanism control unit according to the embodiment of the present invention, FIG. 7 is a diagram showing an example of a first image forming unit combination table according to the embodiment of the present invention, and FIG. 8 is an embodiment of the present invention. FIG. 9 is a diagram showing an example of a development voltage adjustment value table in the embodiment of the present invention, FIG. 9 is a diagram showing an example of a concentration detection pattern in the embodiment of the present invention, and FIG. 10 is an example of a coefficient table for calculating concentration in the embodiment of the present invention. 11 is a diagram showing an example of a target print density table in the embodiment of the present invention, and FIG. 12 is a diagram showing an example of a drive time adjustment value table in the embodiment of the present invention.

First, the mechanism control unit 61 sets the adjustment value of the developing voltage and the adjustment value of the LED drive time to the initial values.

Next, the mechanism control unit 61 determines whether the positions and up / down states of the image forming units 20Y, 20M, 20C, 20Bk, and 20W have been changed.

Therefore, the mechanism control unit 61 determines whether or not the first change confirmation condition is satisfied depending on whether or not the power of the printer 10 is turned on by the operator. When the power of the printer 10 is not turned on and the first change confirmation condition is not satisfied, the mechanism control unit 61 determines whether the second change confirmation condition is satisfied depending on whether the device cover is closed. do.

Then, when the power of the printer 10 is turned on, or when the device cover is closed, that is, when one of the first and second change confirmation conditions is satisfied, the density correction processing unit Pr1 uses the device. The positions of the image forming units 20Y, 20M, 20C, 20Bk, and 20W attached to the main body Bd are determined.

Further, the density correction processing unit Pr1 determines the up / down state of each image forming unit 20Y, 20M, 20C, 20Bk, 20W.

Therefore, a tag (not shown) as a storage element for identifying the image forming unit is attached to each image forming unit 20Y, 20M, 20C, 20Bk, 20W, and the toner contained in each toner cartridge 25 is attached to each tag. Information on the image forming units 20Y, 20M, 20C, 20Bk, 20W, etc., such as the type, color, and remaining amount of the image is recorded. Then, a reading unit (not shown) for reading information of the image forming units 20Y, 20M, 20C, 20Bk, 20W is provided on the apparatus main body Bd, and the image forming unit 20Y, 20M, 20C, 20Bk, 20W is provided by the reading unit. The information is read. Therefore, the density correction processing unit Pr1 can determine the positions of the image forming units 20Y, 20M, 20C, 20Bk, and 20W, and the image forming units 20Y, 20M, 20C, 20Bk, and 20W are placed in the up state. It can be determined whether it is in the down state or in the down state. It should be noted that a sensor for mechanically detecting whether or not each image forming unit 20Y, 20M, 20C, 20Bk, 20W is attached to the apparatus main body Bd can be arranged.

Further, the density correction processing unit Pr1 creates a first image forming unit combination table Tb1 shown in FIG. 7 based on the positions and up / down states of the image forming units 20Y, 20M, 20C, 20Bk, and 20W. Storage unit 64 Records.

In ST1 to ST5 in the first image forming unit combination table Tb1, the positions where the image forming unit is attached are set as Y, M, C, K, W from the upstream side to the downstream side in the traveling direction of the intermediate transfer belt. , Representing the image forming units 20Y, 20M, 20C, 20Bk, 20W, and 4, 3, 2, 1, 0 attached to Y, M, C, K, W are downstream in the traveling direction of the intermediate transfer belt 35. The number of image forming units placed down on the side. Further,-indicates that the image forming unit is placed in the up state.

For example, the YMCKW in the color order of the toners in the first image forming unit combination table Tb1 is located in the order of the image forming units 20Y, 20M, 20C, 20Bk, 20W from the upstream side to the downstream side in the traveling direction of the intermediate transfer belt 35. Y4, M3, C2, K1, and W0 have the image forming unit 20Y at the position ST1, the image forming unit 20M at the position ST2, the image forming unit 20C at the position ST3, and the image at the position ST4. The forming unit 20Bk indicates that the image forming unit 20W is arranged at the position ST5.

Further, the WYMCK in the color order of the toners in the first image forming unit combination table Tb1 is located in the order of the image forming units 20W, 20Y, 20M, 20C, and 20Bk from the upstream side to the downstream side in the traveling direction of the intermediate transfer belt 35. -, Y3, M2, C1, K0 indicate that the image forming unit is placed in the up state at the position ST1, the image forming unit 20Y is placed at the position ST2, and the image forming unit 20M is placed at the position ST3. However, the image forming unit 20C is arranged at the position ST4, and the image forming unit 20Bk is arranged at the position ST5.

Subsequently, the density correction processing unit Pr1 refers to the development voltage adjustment value table Tb2 shown in FIG. 8, and detects the density of each image forming unit 20Y, 20M, 20C, 20Bk, 20W, and on the intermediate transfer belt 35. The adjustment value of the development voltage set for each print duty when forming the pattern Pt1 is read out.

W, K, Y, M, and C in the development voltage adjustment value table Tb2 represent the image forming units 20W, 20Bk, 20Y, 20M, and 20C. Further, ΔWDB, ΔKDB, ΔYDB, ΔMDB, and ΔCDB are adjustment values of the development voltage applied to the development rollers 27 of the image forming units 20W, 20Bk, 20Y, 20M, and 20C, and the adjustment values ΔWDB, ΔKDB, ΔYDB, and ΔMDB. , ΔCDB subscripts 30, 70, 100 are in the print duty state, and upper subscripts 4, 3, 2, 1, 0 are in the down state on the downstream side of the image forming unit for correcting the development voltage. Represents the number of image forming units placed.

That is, ΔWDB ₃₀ ⁴ , ΔKDB ₃₀ ⁴ , ΔYDB ₃₀ ⁴ , ΔMDB ₃₀ ⁴ , and ΔCDB ₃₀ ⁴ in the development voltage adjustment value table Tb2 will correct the development voltage among the image forming units 20W, 20Bk, 20Y, 20M, and 20C. When the number of image forming units placed in the down state on the downstream side of the image forming unit is 4, the development voltage is adjusted when a color image is formed on the paper P with a printing duty of 30 [%]. The value is ΔDB.

Subsequently, the density correction processing unit Pr1 sends the read adjustment values ΔWDB, ΔKDB, ΔYDB, ΔMDB, and ΔCDB to the high voltage control unit 65, and the high voltage control unit 65 is subjected to the development voltage generated by the development voltage generation unit Pw2. It is instructed to add the adjustment values ΔWDB, ΔKDB, ΔYDB, ΔMDB, and ΔCDB.

As a result, the development voltage is corrected and the thickness of the thin layer of toner formed on the developing roller 27 changes, so that the density of the color image formed on the paper P is corrected.

On the other hand, if the power of the printer 10 is not turned on, the device cover is not closed, and the first and second change confirmation conditions are not satisfied, the image forming units 20Y, 20M, 20C, 20Bk, and 20W are used. Since the position has not been changed and the up / down state has not been changed, the density correction processing unit Pr1 corrects the development voltage as described above.

Next, when the concentration correction processing unit Pr1 is instructed by the mechanism control unit 61 to calculate the concentration of the concentration detection pattern Pt1, the concentration detection pattern Pt1 shown in FIG. 9 is formed on the intermediate transfer belt 35.

The concentration detection pattern Pt1 is formed so as to extend in the traveling direction (arrow C direction) of the intermediate transfer belt 35, and is composed of 15 detection sites having a length of Lp [mm].

K, C, M, Y, and W at each of the detection sites represent black, cyan, magenta, yellow, and white colors, and 30%, 70%, and 100% represent print duty.

Subsequently, the concentration correction processing unit Pr1 calculates the concentration of the concentration detection pattern Pt1 formed on the intermediate transfer belt 35 by the concentration sensor 44.

Next, the density correction processing unit Pr1 corrects the LED drive time based on the sensor output of the density sensor 44.

Therefore, the concentration correction processing unit Pr1 reads the sensor output of the concentration sensor 44, and reads out the coefficient for concentration calculation with reference to the coefficient table Tb3 for calculating the concentration shown in FIG.

W, K, Y, M, and C in the density calculation coefficient table Tb3 represent the image forming units 20W, 20Bk, 20Y, 20M, and 20C. Further, W (A), K (A), Y (A), M (A), and C (A) are used when calculating the concentration of the concentration detection pattern Pt1 based on the output voltage of the sensor output of the concentration sensor 44. W (B), K (B), Y (B), M (B), and C (B) are the coefficients of the concentration detection pattern Pt1 based on the output voltage of the sensor output of the concentration sensor 44. It is a coefficient at the time of calculation, and is a coefficient W (A), K (A), Y (A), M (A), C (A), W (B), K (B), Y (B), M. The upper subscript X attached to (B) and C (B) represents the number of image forming units placed in the down state on the downstream side of the image forming unit for which the driving time of the LED is to be corrected.

For example, when the image forming unit for which the LED drive time is to be corrected is the image forming unit 20C and the number of image forming units placed in the down state on the downstream side of the image forming unit 20C is 4, 30 [. When the density of the density detection pattern Pt1 formed by the printing duty of%], 70 [%], and 100 [%] is calculated, the density calculation coefficient read from the density calculation coefficient table Tb3 is C ₃₀ ⁴ (A), C ₇₀ ⁴ (A), C ₁₀₀ ⁴ (A), C ₃₀ ⁴ (B), C ₇₀ ⁴ (B), C ₁₀₀ ⁴ (B).

When the output voltages of the sensor outputs of the concentration sensor 44 are CV ₃₀ ⁴ , CV ₇₀₄ , and CV ₁₀₀ ⁴ , the densities COD ₃₀ ⁴ , COD ₇₀₄ , and COD ₁₀₀ ⁴ of the concentration detection pattern Pt ¹ are expressed by the following equations ⁽ It is calculated by 1) to (3).

COD ₃₀ ⁴ = C ₃₀ ⁴ (A) x CV ₃₀ ⁴ + C ₃₀ ⁴ (B) …… (1)
COD ₇₀ ⁴ = C ₇₀ ⁴ (A) x CV ₇₀ ⁴ + C ₇₀ ⁴ (B) …… (2)
COD ₁₀₀ ⁴ = C ₁₀₀ ⁴ (A) x CV ₁₀₀ ⁴ + C ₁₀₀ ⁴ (B) …… (3)
Subsequently, the density correction processing unit Pr1 reads the target density COD _{T30 and COD T70 COD T100 of the density detection pattern Pt1 with reference to the target print density table Tb4 shown in FIG. 11, and reads the target density COD T30 and COD T70 COD T100} . And the differences between the concentrations COD ₃₀ ⁴ , COD 704, and COD ₁₀₀ ⁴ , _{ΔCOD T30} , ^ΔCOD _T70 , and ΔCOD _T100 are calculated.

W, K, Y, M, and C in the target print density table Tb4 represent image forming units 20W, 20Bk, Y20, 20M, 20C. Further, WOD _T , KOD _T , YOD _T , MOD _T , and COD _T are the target concentrations of the concentration detection pattern Pt1, and the subscripts attached to the target concentrations WOOD _T , KOD _T , YOD _T , MOD _T , and COD _T. 30, 70, 100 represent the print duty.

For example, WOD _T30 , KOD _T30 , YOD _T30 , MOD _T30 , and COD _T30 have a density of 30 [%] in each image forming unit 20W, 20Bk, 20Y, 20M, 20C that attempts to correct the LED drive time. This is the target concentration when forming the detection pattern Pt1.

By the way, since the density of the image is proportional to the drive time of the LED, the density correction processing unit Pr1 has a drive time adjustment value table Tb5 as shown in FIG. 12 based on the differences ΔCOD _T30 , ΔCOD _T70 , and ΔCOD _T100 . Can be acquired in the storage unit 64.

Further, W, K, Y, M, and C in the drive time adjustment value table Tb5 represent image forming units 20W, 20Bk, 20Y, 20M, and 20C. Then, ΔWDK, ΔKDK, ΔYDK, ΔMDK, and ΔCDK are adjustment values for correcting the LED drive time in each of the image forming units 20W, 20Bk, 20Y, 20M, and 20C. The subscripts 30, 70, and 100 attached to the adjustment values ΔWDK, ΔKDK, ΔYDK, ΔMDK, and ΔCDK try to correct the print duty, and the superscripts 4, 3, 2, 1, and 0 try to correct the drive time. It represents the number of image forming units placed in the down state on the downstream side of the image forming unit.

That is, ΔWDK ₃₀ ⁴ , ΔKDK ₃₀ ⁴ , ΔYDK ₃₀ ⁴ , ΔMDK ₃₀ ⁴ , and ΔCDK ₃₀ ⁴ in the drive time adjustment value table Tb 5 are the image forming units 20W, 20Bk, 20Y, 20M, 20C for which the drive time is to be corrected. This is an adjustment value for forming a color image on paper P with a print duty of 30 [%] when the number of image forming units placed in the down state on the downstream side of the image forming unit is 4.

Subsequently, the density correction processing unit Pr1 refers to the drive time adjustment value table Tb5 when forming an image on the paper P, and reads and reads the LED drive time adjustment values ΔWDK, ΔKDK, ΔYDK, ΔMDK, and ΔCDK. The adjusted values ΔWDK, ΔKDK, ΔYDK, ΔMDK, and ΔCDK are sent to the LED head interface unit If2, and the LED head interface unit If2 is instructed to add the adjustment values ΔWDK, ΔKDK, ΔYDK, ΔMDK, and ΔCDK to the LED drive time. ..

As a result, the driving time of the LED changes in each LED head 24, so that the density of the color image formed on the paper P is corrected.

In this way, when the density correction process is completed, the mechanism control unit 61 instructs the command / image processing unit 60 to start printing the print job.

Next, the flowchart will be described.
Step S1 The mechanism control unit 61 sets the adjustment value of the developing voltage and the adjustment value of the LED drive time to the initial values.
Step S2 The mechanism control unit 61 determines whether or not the power of the printer 10 is turned on. If the power of the printer 10 is turned on, the process proceeds to step S4, and if the power of the printer 10 is not turned on, the process proceeds to step S3.
Step S3 The mechanism control unit 61 determines whether or not the device cover is closed. If the device cover is closed, the process proceeds to step S4, and if the device cover is not closed, the process proceeds to step S6.
Step S4 The density correction processing unit Pr1 determines the positions of the image forming units 20Y, 20M, 20C, 20Bk, and 20W.
Step S5 The density correction processing unit Pr1 determines the up / down state of each image forming unit 20Y, 20M, 20C, 20Bk, 20W.
Step S6 The density correction processing unit Pr1 corrects the development voltage.
Step S7 The concentration correction processing unit Pr1 forms the concentration detection pattern Pt1 on the intermediate transfer belt 35, and calculates the concentration of the concentration detection pattern Pt1 by the concentration sensor 44.
Step S8 The density correction processing unit Pr1 corrects the LED drive time based on the sensor output of the density sensor 44.
Step S9 The mechanism control unit 61 instructs the command / image processing unit 60 to start printing the print job, and ends the processing.

In this way, when printing is completed for the predetermined print job, the waste toner amount calculation processing unit Pr2 performs the waste toner amount calculation processing, calculates the amount of waste toner generated by printing, and displays it on the display unit 19. do.

Next, the operation of the waste toner amount calculation processing unit Pr2 will be described.

13 is a diagram showing an example of a coefficient table for calculating secondary transfer efficiency in the embodiment of the present invention, FIG. 14 is a diagram illustrating an example of the position of each image forming unit in the embodiment of the present invention, and FIG. 15 is a diagram illustrating an example of the position of each image forming unit. A figure showing an example of the toner color of the toner image transferred in the primary transfer unit in the embodiment of the present invention, FIG. 16 is from an image forming unit for calculating the density of the density detection pattern in the embodiment of the present invention. The relationship diagram between the output voltage and the density of the density detection pattern when the number of image forming units on the downstream side is different, FIG. 17 is downstream from the image forming unit for calculating the density of the density detection pattern in the embodiment of the present invention. It is a relationship diagram of the output voltage and the density | density of the density detection pattern when the toner color of the toner image in the side image forming unit is different. In FIG. 16, the horizontal axis represents the output voltage CV, the vertical axis represents the concentration COD of the concentration detection pattern Pt1, the horizontal axis represents the output voltage YV, and the vertical axis represents the concentration YOD of the concentration detection pattern Pt1. ..

In the present embodiment, the waste toner amount calculation processing unit Pr2 (FIG. 1) instructs the LED head interface unit If2 to count the number of times the LED is driven every time printing is performed for a predetermined number of print jobs. , Reads the count value of the number of drives and converts it to the dot count value. Therefore, the waste toner amount calculation processing unit Pr2 calculates the amount of toner δW used when printing is performed for a predetermined number of print jobs based on the dot count value.

By the way, when the primary transfer efficiency in the primary transfer unit is η1 and the secondary transfer efficiency in the secondary transfer unit is η2, a second cleaning device 45 is performed as printing is performed for a predetermined number of print jobs. The amount δD of the waste toner discarded according to (FIG. 2) is calculated by the following formula (4).

δD = δW × η1 × (100-η2) …… (4) However, when the development voltage and the drive time are corrected in the density correction process by the density correction processing unit Pr1, the toner image formed on the intermediate transfer belt 35 is formed. Since the amount of toner in the above changes, the secondary transfer efficiency η2 fluctuates, and the amount of discarded toner δD cannot be calculated accurately.

That is, when the toner image is transferred to the intermediate transfer belt 35 in the primary transfer unit of the predetermined image forming unit, the toner image on the intermediate transfer belt 35 is subsequently transferred to the image forming unit on the downstream side of the predetermined image forming unit. Since the number of times of passing through the primary transfer unit varies depending on the position of the predetermined image forming unit, the toner charge distribution of the toner image of the toner image transferred to the intermediate transfer belt 35 is the primary of the image forming unit on the downstream side. It changes each time it passes through the transfer section.

Further, since the height of the primary transfer voltage required to transfer the toner image to the intermediate transfer belt 35 differs depending on the color of the toner, what color of toner image is transferred in the primary transfer unit of the image forming unit on the downstream side. The charge distribution also changes depending on the case.

Therefore, since the secondary transfer efficiency η2 in the secondary transfer section changes as the toner charge distribution of the toner image on the intermediate transfer belt 35 changes, the amount δD of the discarded toner can be accurately determined by the above equation (4). It may not be possible to calculate.

By the way, for example, when the number of image forming units placed in the down state on the downstream side of the image forming unit 20C is n, the cyan image transferred to the intermediate transfer belt 35 in the primary transfer unit is secondarily transferred. Assuming that the secondary transfer efficiency when the toner image is transferred to the paper P in the unit is CK ⁿ , the secondary transfer efficiency CK ⁿ is the ratio of the mass of how much the toner image on the intermediate transfer belt 35 is transferred to the paper P. Therefore, assuming that the mass of the toner image on the intermediate transfer belt 35 is Gb and the mass of the toner image on the paper P is Gp, the secondary transfer efficiency CK ⁿ is calculated by the following equation (5). It is calculated.

CK ⁿ = 100 × Gp / Gb …… (5)
In order to calculate the secondary transfer efficiency CK ⁿ , the mass Gb of the toner image on the intermediate transfer belt 35 and the mass Gp of the toner image on the paper P are required, but the mass of the toner image on the paper P is required. It is known by experiments that Gb is proportional to the density of the toner image on the paper P, and that the output voltage of the sensor output by the density sensor 44 is proportional to the mass Gb of the toner image on the intermediate transfer belt 35. There is.

Therefore, the waste toner amount calculation processing unit Pr2 calculates the mass Gb of the toner image on the intermediate transfer belt 35 based ^on the output voltages CV ₃₀ ⁴ , CV ₇₀₄ , and CV ₁₀₀ ⁴ in the above equations (1) to (3). Then, the mass Gp of the toner image on the paper P is calculated based ^on the concentrations COD ₃₀ ⁴ , COD ₇₀₄ , and COD ₁₀₀ ⁴ calculated by the above equations (1) to (3).

Therefore, the waste toner amount calculation processing unit Pr2 refers to the coefficient table _Tb6 for calculating the secondary transfer efficiency shown in FIG. 13, and the intermediate transfer belt 35 is based ^on the output voltages CV ₃₀ ⁴ , CV 704, and CV ₁₀₀ ⁴ . To calculate the mass Gp of the toner image on the paper P based on the coefficients 1 and ² for calculating the mass Gb of the toner image above, α and β, and the concentrations COD ₃₀ ⁴ , COD ₇₀₄ , and COD ₁₀₀ ⁴ . Γ and ε are read out as the coefficients 1 and 2 of, and the masses Gb and Gp are calculated by the following equations (6) and (7).

Gb = α × CV + β …… (6)
Gp = γ × COD + ε …… (7)
Further, the waste toner amount calculation processing unit Pr2 substitutes the masses Gb and Gp into the above formula (5), and calculates the secondary transfer efficiency CK ⁿ by the following formula (8).

CK ⁿ = 100 × Gp / Gb
= 100 × (α × CV + β) / (γ × COD + ε) …… (8)
In the above equations (6) to (8), for convenience, the output voltages CV ³⁰⁴ , CV ⁷⁰⁴ , and CV ₁₀₀ ⁴ are set as _CVs , and the concentrations COD ₃₀ ⁴ , _{COD 704} , and COD ₁₀₀ ⁴ of the concentration detection pattern Pt ¹ are used. Let it be COD.

For example, when the output voltage CV of the sensor output when the density detection pattern Pt1 formed with a print duty of 100 [%] is detected by the density sensor 44 is CV ₁₀₀ ⁿ , the density COD ₁₀₀ ⁿ is calculated by the above equation (3). ), Change the superscript 4 to n
COD ₁₀₀ ⁿ = C ₁₀₀ ⁿ (A) x CV ₁₀₀ ⁿ + C ₁₀₀ ⁿ (B)
Since it can be expressed by, the secondary transfer efficiency CK ⁿ is calculated by the following equation (9).

CK ⁿ = 100 × (α × (α × (C ₁₀₀ ⁿ (A) × CV ₁₀₀ ⁿ + C ₁₀₀ ⁿ (B)) + β) / (γ × COD + ε) …… (9)
As described above, when the number of image forming units placed in the down state on the downstream side of the image forming unit 20C is n, the cyan-colored toner image on the intermediate transfer belt 35 is transferred to the paper P. The secondary transfer efficiency CK ⁿ can be calculated based on the output voltage CV ₁₀₀ ⁿ of the sensor output of the density sensor 44 obtained by the density correction process.

Subsequently, the waste toner amount calculation processing unit Pr2 performs printing on a predetermined number of print jobs, with the primary transfer efficiency as η1 and the toner amount used when printing on a predetermined number of print jobs as δW. Amount of cyan-colored waste toner discarded by the second cleaning device 45 δCD
δCD = δW × η1 × (100-CK ⁿ )
Is calculated. The primary transfer efficiency η1 and the secondary transfer efficiency CK ⁿ are expressed as percentages.

Further, the waste toner amount calculation processing unit Pr2 transfers the toner image of another color on the intermediate transfer belt 35, that is, each color of white, black, yellow, and magenta to the paper P by the same method. The secondary transfer efficiencies WK ⁿ , BK ⁿ , YK ⁿ , and MK ⁿ are calculated, and the amount of waste toner of each color is calculated based on the secondary transfer efficiencies WK ⁿ , BK ⁿ , YK ⁿ , and MK ⁿ . Amount of waste toner when transferring the color toner image on the intermediate transfer belt 35 to the paper P δD
δD = δWD + δBD + δYD + δMD + δCD
Is calculated.

Subsequently, the waste toner amount calculation processing unit Pr2 is a total amount D of waste toner, which is the total (integrated amount) of the amount δD of the waste toner discarded in the waste toner tank 48 after the waste toner tank 48 is replaced.
D = ΣδD
Is calculated.

Then, the waste toner amount calculation processing unit Pr2 represents the ratio of the total amount D of the waste toner to the volume U of the waste toner tank 48, and the waste toner occupancy rate φ.
φ = D / U [%]
Is calculated, and the residual volume ratio φx representing the ratio of the residual volume Ux of the waste toner tank 48 to the volume U of the waste toner tank 48.
φx = 100-φ [%]
Is calculated.

Further, each time the waste toner amount calculation processing unit Pr2 calculates the waste toner amount δD as printing is performed for a predetermined number of print jobs, the waste toner amount calculation processing unit Pr2 represents the state of containing the waste toner in the waste toner tank 48, respectively. , Amount δD of waste toner, total amount D of waste toner D, waste toner occupancy rate φ and remaining volume ratio φx are recorded in the storage unit 64. Further, the waste toner amount calculation processing unit Pr2 notifies the operator by displaying the remaining volume ratio φx on the display unit 19 at a predetermined timing, for example, at a timing when the remaining volume ratio φx decreases by 10 [%]. do. Then, when the residual volume ratio φx becomes smaller than the preset threshold value φxth, the waste toner amount calculation processing unit Pr2 displays a message prompting the replacement of the waste toner tank 48 on the display unit 19 and notifies the operator.

Therefore, it is possible to prevent the waste toner tank 48 from being filled with the waste toner. In the present embodiment, a message prompting the replacement of the remaining volume ratio φx and the waste toner tank 48 is displayed on the display unit 19 and the operator is notified, but the total amount of the waste toner D and the waste toner occupancy rate φ. Etc. can be notified to the operator by displaying the above on the display unit 19.

By the way, as described above, the amount of waste toner δD is the number of image forming units that are placed in the down state on the downstream side when the toner image is transferred to the intermediate transfer belt 35 in a predetermined image forming unit. Not only depends on the color of the toner in the toner image transferred in the primary transfer unit of the image forming unit on the downstream side.

Therefore, even if the number of image forming units placed in the down state on the downstream side is the same, depending on the color of the toner of the toner image transferred in the primary transfer unit of the image forming unit on the downstream side, the waste toner may be used. The quantity δD cannot be calculated accurately.

For example, in the example of the position of each image forming unit shown in FIG. 14, ST1 to ST5 are the positions where the image forming unit is attached, and Y, M, C, K, and W are the image forming units 20Y, 20M, 20C, 20Bk. , 20W, and 4, 3, 2, 1, 0 attached to Y, M, C, K, and W are image formations that are placed in a down state on the downstream side in the traveling direction of the intermediate transfer belt 35. The number of units. Further, Y', M', and C'represent the image forming units 20Y, 20M, and 20C when the image forming unit 20Bk is attached to the position ST1 and the image forming unit 20W is attached to the position ST5.

That is, at the position of each image forming unit shown in FIG. 14, the number n of the image forming units placed in the down state on the downstream side of the image forming unit 20Y is 3, and the image forming unit 20W is placed at the position ST1. The toner color of the toner image transferred in the primary transfer unit of the image forming unit on the downstream side of the image forming unit 20Y is different depending on whether the image is formed or the image forming unit 20Bk is placed. That is, as shown in FIG. 15, assuming that the toner color of the toner image transferred in the primary transfer unit of the image forming unit 20Y downstream of the image forming unit 20Y is color 1, color 2, and color 3, the position ST1 is reached. When the image forming unit 20W is placed, the toner color of the toner image transferred in the primary transfer section of the image forming unit downstream of the image forming unit 20Y is magenta, cyan, and black, whereas the color is at position ST1. When the image forming unit 20Bk is placed, the toner colors of the toner image transferred in the primary transfer unit of the image forming unit downstream of the image forming unit 20Y are magenta, cyan, and white.

As described above, the secondary transfer efficiency when the color 1, the color 2, and the color 3 are magenta, cyan, and black is set to YK ³ , and the secondary transfer efficiency when the color 1, the color 2, and the color 3 are magenta, cyan, and white is set to YK 3. Assuming that the secondary transfer efficiency is YK ^{3 '} , the secondary transfer efficiencies YK ³ and YK 3'are different from each other, but they can be calculated by the same method as when calculating the secondary transfer efficiency CK ⁿ .

Then, in FIG. 16, L1 is a density detection pattern Pt1 formed with a print duty of 100 [%] when the number of image forming units placed in the down state on the downstream side of the image forming unit 20C is 4. It is a line showing the relationship between the output voltage CV ₁₀₀ ⁴ and the density COD ₁₀₀ when the density of is detected, and L2 is the number of image forming units placed in the down state on the downstream side of the image forming unit 20C is 0. In this case, it is a line showing the relationship between the output voltage CV ₁₀₀ ⁰ and the density COD ₁₀₀ when the density of the density detection pattern Pt1 formed with the print duty of 100 [%] is detected.

The waste toner amount calculation processing unit Pr2 calculates the mass Gb of the toner image on the intermediate transfer belt 35 based on the output voltage CV ₁₀₀ ⁴ shown in FIG. 16, and the toner on the paper P is calculated based on the density COD ₁₀₀ ⁴ . The mass Gp of the image is calculated, and in the above formula (8), the superscript n is set to 4 and the CV is set to CV ₁₀₀ , and the secondary transfer efficiency CK ⁴
CK ⁴ = 100 × Gp / Gb
= 100 × (α × CV ₁₀₀ ⁴ + β) / (γ × COD ₁₀₀ ⁴ + ε)
Is calculated. In this case, the output voltage CV ₁₀₀ ⁴ is the output voltage of the sensor output of the concentration sensor 44 when the concentration correction process is performed, and the concentration COD ₁₀₀ ⁴ is read from the concentration calculation coefficient table Tb 3 shown in FIG. It can be calculated based on the obtained coefficients C ⁴ (A) and C ⁴ (B).

Further, the waste toner amount calculation processing unit Pr2 calculates the mass Gb of the toner image on the intermediate transfer belt 35 based on the output voltage CV ₁₀₀ ⁰ shown in FIG. 16, and on the paper P based on the density COD ₁₀₀ ⁰ . The mass Gp of the toner image of the above is calculated, and in the above formula (8), the superscript n is set to 4, the CV is set to CV ₁₀₀ , and the secondary transfer efficiency CK ⁰ .
CK ⁰ = 100 × Gp / Gb
= 100 × (α × CV ₁₀₀ ⁰ + β) / (γ × COD ₁₀₀ ⁰ + ε)
Is calculated. In this case, the output voltage CV ₁₀₀ ⁰ is the output voltage of the sensor output of the concentration sensor 44 when the concentration correction process is performed, and the concentration COD ₁₀₀ ⁰ is a coefficient read from the concentration calculation coefficient table Tb3. It can be calculated based on C ⁰ (A) and C ⁰ (B).

Then, in FIG. 17, L3 is a density detection pattern formed with a print duty of 100 [%] when the toner color of the image forming unit downstream of the image forming unit 20Y is magenta, cyan, or black. It is a line showing the relationship between the output voltage YV ₁₀₀ ³ and the density YOD ₁₀₀ when the density of Pt 1 is detected. In L4, the toner color of the image forming unit downstream from the image forming unit 20Y is magenta, cyan, and It is a line showing the relationship between the output voltage YV ₁₀₀ ^3'and the density YOD ₁₀₀ when the density of the density detection pattern Pt1 formed with the print duty of 100 [%] is detected in the case of white.

The waste toner amount calculation processing unit Pr2 calculates the mass Gb of the toner image on the intermediate transfer belt 35 based on the output voltage YV ₁₀₀ ^3'shown in FIG. 17, and on the paper P based on the concentration YOD ₁₀₀ ³ . Calculate the mass Gp of the toner image, and the secondary transfer efficiency YK ³
YK ³ = 100 × Gp / Gb
= 100 × (α × YV ₁₀₀ ³ + β) / (γ × YOD ₁₀₀ ³ + ε)
Is calculated. Also in this case, the output voltage YV ₁₀₀ ³ is the output voltage of the sensor output of the concentration sensor 44 when the concentration correction process is performed, and the concentration YOD ₁₀₀ ³ is read out from the concentration calculation coefficient table Tb3. It can be calculated based on the coefficients Y ³ (A) and Y ³ (B).

Further, the waste toner amount calculation processing unit Pr2 calculates the mass Gb of the toner image on the intermediate transfer belt 35 based on the output voltage YV ₁₀₀ 3'shown in FIG. 17, and the paper P is based on the density YOD ₁₀₀ ^{3' .} The mass Gp of the above toner image is calculated, and the secondary transfer efficiency YK ^3'
YK ^3' = 100 x Gp / Gb
= 100 x (α x YV ₁₀₀ ^3' + β) / (γ x YOD ₁₀₀ ^3' + ε)
Is calculated. Also in this case, the output voltage YV ₁₀₀ ^3'is the output voltage of the sensor output of the concentration sensor 44 when the concentration correction process is performed, and the concentration YOD ₁₀₀ ^3'is read out from the concentration calculation coefficient table Tb3. It can be calculated based on the obtained coefficients Y ³ (A) and Y ³ (B).

Therefore, the waste toner amount calculation processing unit Pr2 has a waste toner amount ^δYD based on the primary transfer efficiency η1 and the secondary transfer efficiency YK3.
δYD = δW × η1 × (100-YK ³ )
Is calculated, and the amount of waste toner δYD is based on the primary transfer efficiency η1 and the secondary transfer efficiency YK ^3' .
δYD = δW × η1 × (100-YK ^{3 ′} )
Is calculated.

As described above, in the present embodiment, the density detection pattern calculated based on the position and up / down state of each image forming unit 20Y, 20M, 20C, 20Bk, 20W, and the output voltage of the sensor output of the density sensor 44. Based on the density of Pt1, the density of the color image formed on the paper P is corrected, and the amount of waste toner δD generated by printing is calculated based on the output voltage and the density of the density detection pattern Pt1. , Secondary transfer when the secondary transfer is performed when the operator changes the position of each image forming unit 20Y, 20M, 20C, 20Bk, 20W or puts a predetermined image forming unit in the up state. Even if the efficiency changes, the amount of waste toner δD can be calculated accurately.

Therefore, since the remaining volume Ux of the waste toner tank 48 is accurately calculated, the operator is properly urged to replace the waste toner tank 48.

In the present embodiment, as shown in FIG. 9, the concentration detection pattern Pt1 is composed of 15 detection sites, but the number of detection sites can be increased.

FIG. 18 is a diagram showing another example of the concentration detection pattern in the embodiment of the present invention.

In the figure, Pt2 is a concentration detection pattern, and the concentration detection pattern Pt2 is formed so as to extend in the traveling direction (arrow C direction) of the intermediate transfer belt 35, and has a length of Lp [mm] of 30 pieces. It consists of detection sites.

At each detection site, Y, M, C, K, W represent yellow, magenta, cyan, black and white colors, and 15%, 30%, 50%, 70%, 85% and 100% have print duty. show.

By increasing the number of detection sites in this way, the concentration of the concentration detection pattern Pt2 can be calculated in detail, so that the concentration correction process can be performed with high accuracy.

Further, in the present embodiment, white toner is used as the special color toner, but a toner having brilliance, a clear toner, or the like can be used as the special color toner.

Further, although the printer 10 is described in the above embodiment, the present invention can be applied to an image forming apparatus such as a copying machine, a facsimile, and a multifunction device.

The present invention is not limited to the above-described embodiment, and various modifications can be made based on the gist of the present invention, and these are not excluded from the scope of the present invention.

10 Printer 20Y, 20M, 20C, 20Bk, 20W Image forming unit 21 Photoreceptor drum 24 LED head 27 Development roller 35 Intermediate transfer belt 41, 43 Transfer roller 44 Concentration sensor 45 Second cleaning device 48 Waste toner tank Bd Device body P Paper Pr1 Concentration correction processing unit Pr2 Waste toner amount calculation processing unit Pt1, Pt2 Concentration detection pattern

Claims (10)

(A) A plurality of image carriers and a developer carrier that develops an electrostatic latent image formed on the image carrier to form a developer image and is movably arranged with respect to the main body of the apparatus. Image forming unit and
(B) Arranged so as to face the image carrier of each image carrier, one or more drive elements are driven according to the image signal, and the surface of the image carrier is exposed to form the electrostatic latent image. With the exposure equipment
(C) A first transfer member that transfers the developer image formed on each image carrier to an intermediate transfer member and performs primary transfer, and
(D) A second transfer member that transfers the developer image on the intermediate transfer member to a medium and performs secondary transfer, and
(E) A cleaning device that removes the developer image remaining on the intermediate transfer member after the secondary transfer is performed and stores it in the waste developer storage unit.
(F) A pattern detection unit that detects the concentration detection pattern formed on the intermediate transfer member, and
(G) To the density of the density detection pattern calculated based on the position of each image forming unit, the detached state of each image forming unit with respect to the intermediate transfer member, and the output voltage of the sensor output of the pattern detection unit. Based on the density correction processing unit that corrects the density of the image formed on the medium,
(H) The amount of the waste developer generated by printing is calculated based on the output voltage and the density of the density detection pattern, and the waste developer in the waste developer storage unit is calculated based on the amount of the waste developer. An image forming apparatus including a waste developer amount calculation processing unit that calculates an accommodation state and notifies the operator. According to claim 1, the density correction processing unit corrects the development voltage applied to the developer carrier based on the position of each image forming unit and the detached state of each image forming unit with respect to the intermediate transfer member. The image forming apparatus according to the description. (A) A plurality of image carriers and a developer carrier that develops an electrostatic latent image formed on the image carrier to form a developer image and is movably arranged with respect to the main body of the apparatus. Image forming unit and
(B) Arranged so as to face the image carrier of each image carrier, one or more drive elements are driven according to the image signal, and the surface of the image carrier is exposed to form the electrostatic latent image. With the exposure equipment
(C) A first transfer member that transfers the developer image formed on each image carrier to an intermediate transfer member and performs primary transfer, and
(D) A second transfer member that transfers the developer image on the intermediate transfer member to a medium and performs secondary transfer, and
(E) A cleaning device that removes the developer image remaining on the intermediate transfer member after the secondary transfer is performed and stores it in the waste developer storage unit.
(F) A pattern detection unit that detects the concentration detection pattern formed on the intermediate transfer member, and
(G) The density of the image formed on the medium based on the position and the detached state of each image forming unit and the density of the density detection pattern calculated based on the output voltage of the sensor output of the pattern detection unit. The density correction processing unit that corrects
(H) The amount of the waste developer generated by printing is calculated based on the output voltage and the density of the density detection pattern, and the waste developer in the waste developer storage unit is calculated based on the amount of the waste developer. It has a waste developer amount calculation processing unit that calculates the accommodation state and notifies the operator, and also has a waste developer amount calculation processing unit.
(I) The density correction processing unit is a drive element of the exposure apparatus based on the difference between the density of the density detection pattern and the target print density calculated based on the output voltage of the sensor output of the pattern detection unit. An image forming apparatus characterized in that the drive time is corrected. The density correction processing unit is based on the output voltage of the sensor output of the pattern detection unit and the number of image forming units placed in the down state on the downstream side of the image forming unit for correcting the driving time of the driving element. The image forming apparatus according to claim 3, wherein the density of the density detection pattern is calculated. The waste developer amount calculation processing unit determines the mass of the developer image on the medium calculated based on the density of the concentration detection pattern and the mass of the developer image on the intermediate transfer member calculated based on the output voltage. The image forming apparatus according to claim 4, wherein the amount of the waste developer is calculated based on the method. (A) A plurality of image carriers and a developer carrier that develops an electrostatic latent image formed on the image carrier to form a developer image and is movably arranged with respect to the main body of the apparatus. Image forming unit and
(B) Arranged so as to face the image carrier of each image carrier, one or more drive elements are driven according to the image signal, and the surface of the image carrier is exposed to form the electrostatic latent image. With the exposure equipment
(C) A first transfer member that transfers the developer image formed on each image carrier to an intermediate transfer member and performs primary transfer, and
(D) A second transfer member that transfers the developer image on the intermediate transfer member to a medium and performs secondary transfer, and
(E) A cleaning device that removes the developer image remaining on the intermediate transfer member after the secondary transfer is performed and stores it in the waste developer storage unit.
(F) A pattern detection unit that detects the concentration detection pattern formed on the intermediate transfer member, and
(G) The density of the image formed on the medium based on the position and the detached state of each image forming unit and the density of the density detection pattern calculated based on the output voltage of the sensor output of the pattern detection unit. The density correction processing unit that corrects
(H) The amount of the waste developer generated by printing is calculated based on the output voltage and the density of the density detection pattern, and the waste developer in the waste developer storage unit is calculated based on the amount of the waste developer. It has a waste developer amount calculation processing unit that calculates the accommodation state and notifies the operator, and also has a waste developer amount calculation processing unit.
(I) In the waste developer amount calculation processing unit, a developer image is formed in the output voltage of the sensor output of the pattern detection unit and the image forming unit placed in the down state on the downstream side of each image forming unit. The density of the density detection pattern is calculated based on the color of the developer, the mass of the developer image on the medium calculated based on the density of the density detection pattern, and the intermediate transfer member calculated based on the output voltage. An image forming apparatus characterized in that the amount of waste developer is calculated based on the mass of the developer image. The waste developer amount calculation processing unit calculates the secondary transfer efficiency when the secondary transfer is performed based on the mass of the developer image on the medium and the mass of the developer image on the intermediate transfer member. The image forming apparatus according to claim 5 or 6, wherein the amount of the waste developer is calculated based on the secondary transfer efficiency. The image forming apparatus according to any one of claims 1 to 7, wherein a developer image is formed with a special color developer in a predetermined image forming unit among the image forming units. The image forming apparatus according to claim 8, wherein the special color developer is a white developer. The 8 or 9 according to claim 8 or 9, wherein the image forming unit in which the developer image is formed by the special color developer is located on the most upstream side or the most downstream side in the traveling direction of the intermediate transfer member. Image forming device.

Images